In a new appeal for information, police said they wish to trace a potential witness, the driver of a red Skoda Citigo that was travelling behind the Vauxhall Insignia prior to the collision.
The incident saw a black Vauxhall Insignia and a white Toyota Aygo collide between Station Road and Wolseley Road at around 10.50am on November 21.
A 28-year-old woman was taken to hospital with serious injuries after receiving advanced trauma care on scene, she remains in a critical but stable condition.
Two men were also taken to hospital after suffering minor injuries in the collision.
Witnesses who may have seen either of the vehicles in the Rugeley area prior to the collision or anyone with any relevant dashcam footage is asked to message Staffordshire Police on Facebook or Twitter, quoting incident number 289 of November 21, or call 101.
Alternatively information can be emailed to CIU@staffordshire.pnn.police.uk.